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Investigation of a turbulent spot and a tripped turbulent boundary layer flow using time-resolved tomographic PIV

Schröder, Andreas and Geisler, Reinhard and Elsinga, Gerrit E. and Scarano, Fulvio and Dierksheide, Uwe (2006) Investigation of a turbulent spot and a tripped turbulent boundary layer flow using time-resolved tomographic PIV. Experiments in Fluids, Vol.: 44 (2), pp. 305-316. Springer Verlag Berlin/Heidelberg. DOI: 10.1007/s00348-007-0403-2. ISSN 0723-4864 (PRINT) 1432-114 (ONLINE).

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Official URL: http://www.springerlink.com

Abstract

In this feasibility study the tomographic PIV technique has been applied to time resolved PIV recordings for the study of the growth of a turbulent spot in a laminar flat plate boundary layer and to visualize the topology of coherent flow structures within a tripped turbulent flat plate boundary layer flow. The experiments are performed around (Re<sub>x</sub> )<sup>½</sup> ≈ 450 in a low speed wind-tunnel using four high speed CMOS cameras operating up to 5 kHz. The volume illumination required a multiple-reflection system able to intensify light intensity within the measurement volume. This aspect is deemed essential when a high-speed tomographic PIV system is applied in air flows. The particle image recordings are used for a three dimensional tomographic reconstruction of the light intensity distribution within the illuminated volume. Each pair of reconstructed three-dimensional light distributions is analyzed by 3D spatial cross-correlation using iterative multi-grid schemes with volume-deformation, yielding a correlated time sequence of three-dimensional instantaneous velocity vector volumes. The coherent structures organization is analyzed by 3D-vorticity and -swirling-strength iso-surfaces visualization. In both flow types streaks and hairpin-like or arch vortical structures are most prominent. The data giving insight into the role of these structures for the spatio-temporal arrangement of the wall normal flow exchange mechanisms, especially of the instantaneous Reynolds stress events Q2 and Q4. A description of different self-sustainable flow organizations based on modifications of the hairpin-vortex- and streak- models is given. Two preliminary results are essential: Self-sustainability of a coherent vortical structure depends on the possibility to entrain high momentum fluid, initially Q4. And, stream-wise swirl at the near-wall region of arch or hairpin-like vortices has been observed to be seldom.

Document Type:Article
Additional Information:published online: 13. October 2007
Title:Investigation of a turbulent spot and a tripped turbulent boundary layer flow using time-resolved tomographic PIV
Authors:
AuthorsInstitution or Email of Authors
Schröder, AndreasUNSPECIFIED
Geisler, ReinhardUNSPECIFIED
Elsinga, Gerrit E.Delft University of Technology, Department of Aerospace Engineering, Delft, The Netherlands
Scarano, FulvioDelft University of Technology, Department of Aerospace Engineering, Delft, The Netherlands
Dierksheide, UweLaVision, Göttingen
Date:2 October 2006
Journal or Publication Title:Experiments in Fluids
Refereed publication:Yes
In ISI Web of Science:Yes
Volume:Vol.: 44
DOI:10.1007/s00348-007-0403-2
Page Range:pp. 305-316
Publisher:Springer Verlag Berlin/Heidelberg
Series Name:Journal
ISSN:0723-4864 (PRINT) 1432-114 (ONLINE)
Status:Published
Keywords:turbulent boundary layer, high speed tomographic PIV, 4-D PIV
HGF - Research field:Aeronautics, Space and Transport (old)
HGF - Program:Aeronautics
HGF - Program Themes:Aircraft Research
DLR - Research area:Aeronautics
DLR - Program:L AR - Aircraft Research
DLR - Research theme (Project):L - Flight Physics
Location: Göttingen
Institutes and Institutions:Institute of Aerodynamics and Flow Technology > Experimental Methods
Deposited By: Ilka Micknaus
Deposited On:27 Jul 2007
Last Modified:14 Jan 2010 23:29

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